//public class Main {
//    public static void main(String[] args) {
////        String s1 = String.valueOf(1234);
////        String s2 = String.valueOf(12.34);
////        String s3 = String.valueOf(true);
////        String s4 = String.valueOf(new Student("Hanmeimei", 18));
////        System.out.println(s1);
////        System.out.println(s3);
////        System.out.println(s4);
////       Student stu= new Student("123",12);
////        System.out.println(stu.toString());
////String str = "helloworld" ;
////    System.out.println(str.replaceAll("l", "_"));
////    System.out.println(str.replaceFirst("l", "_"));
////        System.out.println(str);
//        String str = "hello world hello bit" ;
//        str="123";
////        String[] result = str.split(" ",2) ;
////        for(String s: result) {
////            System.out.println(s);
//    }
//}}
//class Student{
//    public String name;
//    public int age;
//    public Student(String name,int age){
//        this.name=name;
//        this.age=age;
//    }
//}